1. Field of Invention
The invention relates to industrial caster wheels.
2. Description of Related Art
Industrial caster wheels are used, for example, as stabilizer casters on a pallet truck. Typical pallet trucks have a single drive wheel and one industrial caster wheel located at each corner. Usually, each industrial caster wheel has a spring member that absorbs shocks while traveling. The spring member also provides stability as the object to which the height-adjustable industrial caster wheel is attached travels over rough surfaces. U.S. Pat. Nos. 6,425,161 and 7,093,319, and pending U.S. Patent Applications (13/085,535 and 13/085,593, filed herewith), each incorporated herein by reference in its entirety, disclose industrial caster wheels having elastomeric spring members.
Pallet trucks are used for a variety of tasks, such as moving pallets between a loading dock and a shipping container or semi trailer or between the loading dock to a storage or redistribution location. When a pallet truck is used to move pallets from the loading dock into the shipping container or semi trailer or from the shipping container or semi trailer onto the loading dock, the operator typically runs the pallet truck at low speeds, due to the limited spaces in the shipping container or semi trailer and/or the loading dock and the typical height offsets between the surface of the loading dock and bottom surface of the shipping container or semi trailer.
The operator's primary concern is to avoid damaging or dislodging any of the goods placed on the pallet as the pallet is being moved. As a result of these considerations, the spring-force adjustable and/or height-adjustable industrial caster wheels are typically set to provide a relatively soft spring force and to allow the pallet truck to move over uneven surfaces while maintaining the pallet as steady and horizontal as possible.
In contrast, after a given pallet has been moved onto the loading dock, other pallet trucks are used to move the pallet to a storage location, a redistribution location and/or another loading dock. For example, upon receiving a number of pallets from a manufacturer at an inbound loading dock of a warehouse, each containing the same goods, some of those pallets may be immediately transferred to a number of outbound loading docks, with each pallet being moved to a different loading dock for shipping to a different retail store. Other ones of those pallets may be moved to storage shelves, where they will be stored until they are shipped to the various retail stores. In another example, those pallets may be moved to a redistribution location, where the various goods are unloaded from the pallets and either placed into storage or repalletized with other goods from other manufacturers and/or other goods from the same manufacturer for delivery to a single retail store.
In these cases, the pallet trucks typically move on a smooth, even floor of the warehouse. The operator's primary concern is to move the pallets as rapidly as possible without tipping over or damaging or dislodging any of the goods placed on the pallet. Thus, the operators run the pallet trucks at high speeds along defined paths. These paths unavoidably include turns, sharp corners and/or moving from one path to another. As a result of these considerations, the spring-force adjustable and/or height-adjustable industrial caster wheels are typically set to provide a relatively stiff spring force and/or to allow the pallet truck to take high-speed turns over relatively even surfaces while avoiding tipping the pallet truck over and/or maintaining the pallet as steady and horizontal as possible.
Typically, a warehouse will employ a large number of pallet trucks, some of which will be used to move pallets between the loading docks and shipping containers and/or semi trailers, others of which will be used to move pallets between the loading docks, storage locations and/or redistribution locations, and still others of which are in a repair bay or the like for repairs or other maintenance. Some such repairs or other maintenance actions include replacing worn drive wheels and/or worn industrial casters.